Prediction of candidates for spinal neuromodulation

ABSTRACT

Described herein are various implementations of systems and methods for determining likelihood of a patient favorably responding to a neuromodulation procedure based on a quantitative or objective score or determination based on a plurality of indicators of pain (e.g., chronic low back pain stemming from one or more vertebral bodies or vertebral endplates of a patient). The systems and methods may involve application of artificial intelligence techniques (e.g., trained algorithms, machine learning or deep learning algorithms, and/or trained neural networks).

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 63/129,374 filed Dec. 22, 2020, the entire content of which is hereby incorporated by reference herein.

FIELD

Described herein are various implementations of systems and methods for identifying patients who may respond favorably to spinal neuromodulation procedures (e.g., ablation of a basivertebral nerve trunk or other intraosseous nerves within a vertebral body, such as nerves innervating vertebral body endplates) to prevent and/or treat back pain (e.g., chronic lower back pain). The systems and methods described herein may incorporate artificial intelligence techniques (e.g., trained algorithms, machine learning or deep learning algorithms, or neural networks). Several embodiments comprise the use of a combination of indicators, or factors, (e.g., characteristics identified from ultra-short time-to-echo (“UTE”) magnetic resonance imaging, characteristics identified from conventional T1- or T2-weighted magnetic resonance imaging, characteristics identified from other imaging modalities, multifidus muscle characteristics (e.g., atrophy), disc calcification, bone turnover, and/or other biomarkers) to identify patients likely to have back pain that would result in a favorable response to the spinal neuromodulation procedures (e.g., back pain stemming from one or more vertebral bodies or vertebral endplates).

BACKGROUND

Back pain is a very common health problem worldwide and is a major cause for work-related disability benefits and compensation. At any given time, low back pain impacts nearly 30% of the US population, leading to 62 million annual visits to hospitals, emergency departments, outpatient clinics, and physician offices. Back pain may arise from strained muscles, ligaments, or tendons in the back and/or structural problems with bones or spinal discs. The back pain may be acute or chronic. Existing treatments for chronic back pain vary widely and include physical therapy and exercise, chiropractic treatments, injections, rest, pharmacological therapy such as opioids, pain relievers or anti-inflammatory medications, and surgical intervention such as vertebral fusion, discectomy (e.g., total disc replacement), or disc repair. Existing treatments can be costly, addictive, temporary, ineffective, and/or can increase the pain or require long recovery times. In addition, existing treatments do not provide adequate relief for the majority of patients and only a small percentage are surgically eligible.

SUMMARY

Applicant's existing technology (the Intracept® System and Procedure provided commercially by Relievant Medsystems, Inc.) offers a safe and effective minimally invasive procedure that targets (e.g., ablates) the basivertebral nerve (and/or other intraosseous nerves or nerves innervating a vertebral endplate) for the relief of chronic low back pain. As disclosed herein, several embodiments provide systems and methods for determining (e.g., via an automated computer-implemented method) whether patients have back pain (e.g., chronic low back pain) originating from one or more vertebral bodies or vertebral endplates, and thus are likely to respond favorably to basivertebral nerve ablation (such as provided by Applicant's existing Intracept® Procedure) or other spinal neuromodulation procedures.

The determination may be based on a combination (e.g., weighted combination) of indicators, or factors. For example, a method may involve generating (e.g., calculating, determining) an objective or quantitative score or other output (e.g., percentage value, numerical value on a scale, binary YES/NO output) based on identification and analysis of the combination of indicators, or factors, indicative of a likelihood of a favorable response (e.g., pain prevention or pain relief) to a particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation treatment within one or more vertebral bodies of the patient). In other words, the method provides an objective or quantitative prediction or assessment (as opposed to a subjective or qualitative prediction or assessment) as to whether the particular spinal neuromodulation procedure is likely to be successful in treating the back pain (e.g., chronic low back pain whose source is in one or more vertebral bodies or vertebral endplates). A clinical professional may decide whether or not to perform the particular spinal neuromodulation procedure based on the objective or quantitative prediction or assessment (e.g., score). For example, if the objective or quantitative prediction or assessment is above a predetermined threshold, a treatment recommendation or treatment protocols may be provided and a clinician may decide to provide treatment or adjust treatment based on the recommendation or protocols.

In accordance with several embodiments, the quantitative score, value, or other output may be generated based on execution of one or more computer-implemented algorithms stored (e.g., on non-transitory computer-readable storage media) and executed by one or more processors (e.g., one or more hardware processors of a server). The quantitative score, value, or other output may be based on a combination (e.g., weighted) combination of multiple indicators. Some indicators may be weighted more, or deemed more important to the quantitative prediction or assessment, than others. For example, the algorithms may generate the quantitative score, value, or other output based on identification and analysis of one or more indicators (e.g., higher-tier or first-tier indicators) that have been deemed through clinical studies or past experience to have a strong correlation with, and/or are more reliable for predicting, the type of back pain that would be successfully treated by the particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure). In some implementations, vertebrae having a quantitative score (e.g., quantitative endplate score) above a threshold may be deemed as potential candidates for treatment (e.g., basivertebral nerve ablation). The quantitative score may comprise a quantitative endplate score based on severity, extent, and/or quantity of identified indicators (e.g., indicators of pain originating from one or more vertebral endplates).

The algorithms (e.g., program instructions stored on non-transitory computer-readable storage media and executed by one or more hardware processors) may also verify, or provide additional confidence in, the quantitative score or other output based on identification and analysis of one or more additional indicators (e.g., lower-tier or second-tier indicators) that may correlate with, and/or be reliable for predicting, the type of back pain (e.g., chronic low back pain) that would be successfully treated by the particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure). The verification or confidence check may advantageously help to reduce false positives or false negatives. Any one factor, or indicator, may not be completely reliable or accurate in predicting likelihood of a successful treatment. In addition, making subjective predictions based on visualization and/or subjective feedback or pain scores from a patient alone may also not be reliably accurate. Identifying indicators and/or generating objective scores based on trained algorithms that have been trained based on former patient data or other reference data can generate more reliable objective scores and treatment recommendations or treatment protocols, thereby resulting in higher patient satisfaction and reducing unnecessary treatments that are likely to be ineffective or providing more specifically tailored treatment protocols.

The type of back pain desired to be treated by the particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure) may be pain originating from one or more vertebral bodies or vertebral endplates (e.g., pain originating from a basivertebral nerve trunk or other intraosseous nerves within a vertebral body or nerves innervating a vertebral endplate). In one embodiment, the type of back pain desired to be treated is not discogenic back pain originating from one or more intervertebral discs. However, in some embodiments, discogenic back pain may be additionally treated even if not the focus or target of the treatment or procedure. The indicators, or factors, may include indicators of pain originating from one or more intervertebral discs.

The algorithms may involve application of artificial intelligence techniques or trained algorithms (e.g., machine learning or deep learning models and algorithms implemented by trained artificial neural networks). Portions of the algorithms may be applied to trained neural networks to facilitate identification of indicators and/or to facilitate calculation of the objective scores. The indicators, or factors, may be identified from, for example, various images obtained using one or more imaging modalities or techniques (e.g., magnetic resonance imaging (“MRI”) images such as conventional T1- and/or T2-weighted MRI imaging, fat suppression MRI imaging, ultrashort time-to-echo (“UTE”) MRI sequenced imaging, Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (“IDEAL”) MRI sequenced imaging, fast spin echo MRI sequenced imaging, computed tomography (“CT”) imaging including single-photon emission computed tomography (“SPECT”) imaging, positron emission tomography (“PET”) bone imaging, X-ray imaging, fluoroscopy, and/or other imaging modalities or techniques).

The images may include images of a particular patient and may also include images of other patients or subjects (e.g., for comparison and/or for training of neural networks for artificial intelligence implementations). The indicators, or factors, may include an identification of one or more characteristics based on the images (e.g., tissue characteristics such as amount of atrophy of paraspinal muscles surrounding a particular vertebral body or a spine in general, vertebral endplate defects or degradation, bone marrow intensity changes such as Modic changes or pre-Modic change characteristics, vertebral fat fraction, shifts in ratio of water to fat in bone marrow, active bone turnover, intervertebral disc calcification, etc.). Modic changes may include, for example, Type 1 Modic changes or Type 2 Modic changes. The one or more indicators, or factors, determined from the images may include edema, inflammation, and/or tissue changes (e.g., tissue lesions, fibrosis, fissures, or other changes in tissue type or characteristics) of bone, bone marrow, and/or endplate lining, contour or profile. Vertebral endplate defects may include, for example, focal defects, erosive defects, rim defects, and corner defects of a vertebral endplate of the vertebral body. The indicators, or factors, may include an identification of particular spinal anatomical characteristics or conditions (e.g., scoliosis, slipped discs, herniated discs, joint dysfunction, spondylosis, osteoarthritis, spinal stenosis, kyphosis, spondylolisthesis, etc.).

The indicators, or factors, may also include assessment of one or more biomarkers (e.g., biomarkers associated with pain, inflammation, or neurotransmission). Biomarkers may also be used to assess whether a particular subject is likely to be a candidate for nerve ablation treatment for treatment of back pain. For example, the biomarkers may be indicative of pre-Modic changes or symptoms likely to result in Modic changes or endplate damage (e.g., inflammation, edema, bone marrow lesions or fibrosis). The assessment of biomarker levels may indicate which vertebral bodies of a particular subject are candidates for treatment to prevent (or reduce the likelihood of) back pain from developing or worsening or to treat existing back pain. The pre-procedure biomarker assessment may also be combined with pre-procedure imaging. The biomarkers may include one or more of: an inflammatory cytokine (e.g., interleukins, interferons, tumor necrosis factors, prostaglandins, and chemokines), pain indicators (e.g., substance P, calcitonin gene-related peptides (CGRPs)), an edema factor, and/or other inflammatory factor. The biomarkers may be obtained, for example, from one or more blood serum samples (e.g., blood plasma). The biomarkers may be obtained over an extended period of time (e.g., a period of days, weeks, or months) or at a single instance in time. Biomarkers may also be identified in the images themselves and may be the tissue characteristics, bone marrow intensity changes, etc. described above.

The indicators, or factors, may also include patient parameters, information, or risk factors such as age, gender, body mass index, bone mineral density measurements, back pain history, indication of prior spine treatments (such as spinal fusion or discectomy procedures), patient-reported outcomes or quality-of-life measures, and/or other known risk factors for vertebral endplate degeneration or defects (such as smoking, occupational or recreational physical demands or situations) in identifying candidate patients and/or candidate vertebral bodies for treatment (e.g., basivertebral nerve ablation).

In accordance with several embodiments, a method of quantitatively predicting likelihood that a particular subject (e.g., human) would respond favorably to basivertebral nerve ablation to treat back pain (e.g., the INTRACEPT® nerve ablation procedure performed using the commercial technology of Relievant Medsystems, Inc.) is provided. The method includes identifying a plurality of indicators of back pain (e.g., chronic low back pain) based on one or more images of at least a portion of the particular subject's spine (e.g., lumbosacral region of the spine). The method may further include quantifying the identified plurality of indicators and calculating an objective score indicative of a likelihood that the particular subject would respond favorably to basivertebral nerve ablation based on the quantifying of the identified plurality of indicators. The entire method or portions of the method may be fully computer-implemented and automated.

The images may be obtained, for example, from one or more of the following imaging modalities: MRI imaging, Tl-weighted MRI imaging, T2-weighted MRI imaging, fat suppression MRI imaging, UTE MRI sequenced imaging, IDEAL MRI sequenced imaging, fast spin echo MRI sequenced imaging, CT imaging, PET bone imaging, X-ray imaging, and fluoroscopy. The images may include images of a particular patient and may also include images of other patients or subjects (e.g., for comparison and/or for training of neural networks for artificial intelligence implementations).

Identifying the plurality of indicators includes identifying one or more bone marrow intensity changes and/or identifying one or more vertebral endplate defects or characteristics of vertebral endplate degeneration. The plurality of indicators may each fall within only one of these two categories in some embodiments. For example, there may be multiple identified indicators (e.g., different spatial locations, different types, different sub-groups or sub-sets within the same category or classification) within the overall category or classification of bone marrow intensity changes or within the overall category or classification of vertebral endplate degeneration or defects. The plurality of indicators may be classified as both bone marrow intensity changes and vertebral endplate defects or characteristics of vertebral endplate degeneration.

Identifying one or more bone marrow intensity changes may include identifying the one or more bone marrow intensity changes as either a Type 1 Modic change or a Type 2 Modic change (or optionally a Type 3 Modic change). Identifying one or more vertebral endplate defects or characteristics of vertebral endplate degeneration may include identifying irregularities or deviations to a normal continuous lining of the vertebral endplate, identifying deviations from a normal contour profile of a vertebral endplate, identifying fat fraction changes, and/or identifying one or more phenotype subtypes of vertebral endplate defects.

Quantifying the identified plurality of indicators may include determining a quantity of the bone marrow intensity changes and/or vertebral endplate defects, determining a level of extent (e.g., spatial distribution, prevalence) of the bone marrow intensity changes and/or vertebral endplate defects, and/or quantifying identified fat fraction changes.

The method may further include determining a confidence level in the objective score based on one or more additional indicators of back pain, such as changes in multifidus muscle characteristics, bone turnover identified in SPECT images, and/or a pain score obtained for the particular subject (e.g., Oswestry Disability Index scores, Visual Analogue pain scores). In other implementations, these additional indicators are used in determining the objective score and not in determining a separate confidence level in the objective score. The method may further include displaying an output of the objective score on a display. The output may be a numerical score on a scale, a binary YES or NO output, a percentage score, and/or the like.

In accordance with several embodiments, a method (e.g., computer-implemented method executed by one or more hardware processors) of quantitatively predicting likelihood that a particular subject would respond favorably to basivertebral nerve ablation to treat back pain includes receiving one or more images (e.g., MRI images) of at least a portion of a spine of the particular subject, applying pre-processing imaging techniques to the one or more images, extracting features from the one or more images to identify a plurality of indicators of back pain, and determining an objective score indicative of a likelihood that the particular subject would respond favorably to basivertebral nerve ablation based on the extracting. The plurality of indicators may include (i) bone marrow intensity changes and/or (ii) vertebral endplate defects or characteristics of vertebral endplate degeneration. Extracting the features from the one or more images may include applying a trained neural network to the one or more images to automatically identify the plurality of indicators of back pain. Determining the objective score may also include applying a trained neural network to the extracted features. In some embodiments, the plurality of indicators may also include additional indicators in addition to bone marrow intensity changes and/or vertebral endplate defects or characteristics of vertebral endplate degeneration.

The method may further include applying one or more rules on the extracted features to generate a confidence level. The one or more rules may be based on one or more additional indicators, such as the additional indicators described herein. The additional indicators, for example, may be an indicator in the other of the two categories (either bone marrow intensity changes or vertebral endplate defects or vertebral endplate degeneration). Determining an objective score may include quantifying the plurality of indicators. The quantifying may be based on an extent (e.g., quantity of indicators, severity of indicators (e.g., size or volume) and/or spatial assessment (prevalence in different locations or regions of a vertebral body or endplate or other location). The method may further include displaying an output of the objective score on a display (e.g., monitor of a desktop or portable computing device).

In accordance with several embodiments, a method (e.g., computer-implemented method comprising stored program instructions executed by one or more hardware processors) of quantitatively predicting likelihood that a particular subject would respond favorably to basivertebral nerve ablation to treat chronic low back pain includes receiving one or more magnetic resonance images (MRIs) of at least a lumbosacral region of a spine of the particular subject, applying pre-processing imaging techniques to the one or more MRIs in order to provide uniformity of the one or more MRIs for feature detection, detecting features from the one or more MRIs to identify a plurality of indicators of chronic low back pain, quantifying the identified plurality of indicators based on an extent of the plurality of indicators, wherein the extent may comprise a quantity, a severity, and/or a spatial assessment, and determining an objective score indicative of a likelihood that the particular subject would respond favorably to a basivertebral nerve ablation procedure based on said quantifying. The plurality of indicators can include both bone marrow intensity changes and vertebral endplate defects or characteristics of vertebral endplate degeneration or multiple indicators (e.g., subgroups or subsets) within only one of these categories or classifications.

In accordance with several embodiments, a computer-implemented method (e.g., executed of stored program instructions by one or more hardware processors) of training a neural network for determining whether or not a particular subject is a likely candidate for a successful basivertebral nerve ablation procedure includes collecting a set of digital images from a database. For example, each digital image may comprise a digital image of at least a portion of a spine of a subject having at least one indicator of back pain (e.g., chronic low back pain stemming from one or more vertebral endplates or vertebral bodies and/or stemming from one or more intervertebral discs). The method further includes applying one or more transformations to each digital image to create a modified set of digital images. The method also includes creating a first training set comprising the collected set of digital images, the modified set of digital images, and a set of digital images of at least a portion of a spine of one or more subjects without any indicators of chronic low back pain (e.g., healthy subjects). The method further includes training the neural network in a first stage using the first training set, creating a second training set for a second stage of training comprising the first training set and digital images of at least a portion of a spine of one or more subjects without any indicators of chronic low back pain that are incorrectly determined as having at least one indicator of chronic low back pain, and training the neural network in a second stage using the second training set.

The digital images may comprise magnetic resonance images, computed tomography images, X-ray images, or other types of images described herein. The digital images may alternatively be analog images in some embodiments.

Applying one or more transformations may include pre-processing the collected set of magnetic resonance images in order to make the magnetic resonance images more uniform for training. The pre-processing may include rotating, cropping, enlarging, reducing, removing noise, segmenting, smoothing, contrast or color enhancing, and/or other image processing techniques. The pre-processing may also include spatial orientation identification, vertebral level identification, general anatomical feature identification, and/or the like. In some embodiments, the pre-processing may be performed by running the images through a previously-trained neural network trained to clean up, enhance, reconstruct, or otherwise improve the quality of images, such as noisy MRI images.

The method may also include identifying indicators of back pain that is likely to be successfully treated by the basivertebral nerve ablation procedure in at least some of the collected set of magnetic resonance images. The method may include identifying images of the collected set of magnetic resonance images for which the subjects were successfully treated by the basivertebral nerve ablation procedure. In some embodiments, the collected set of magnetic resonance images comprises magnetic resonance images of subjects that previously received a spinal fusion or a discectomy procedure, or other procedure that may have resulted in indicators or factors of chronic low back pain (e.g., irritated vertebral endplates or vertebral endplate degeneration or defects or bone marrow intensity changes or multifidus muscle atrophy).

The systems and methods described herein may also be applied to identification of pain other than back pain. For example, the systems and methods may be applied to peripheral nerve pain. In accordance with several embodiments, a method of quantitatively predicting likelihood that a particular subject would respond favorably or unfavorably to neuromodulation includes identifying a plurality of indicators of back and/or peripheral nerve pain, quantifying the identified plurality of indicators, and calculating an objective score indicative of a likelihood that the particular subject would respond favorably or unfavorably to said neuromodulation based on the quantifying. Identifying the plurality of indicators may include identifying one or more bone marrow intensity changes and/or identifying one or more vertebral endplate defects or characteristics of vertebral endplate degeneration. However, other indicators may alternatively or additionally be identified (e.g., for peripheral nerve pain or for back pain other than chronic low back pain).

The plurality of indicators may be identified based on imaging data (such as magnetic resonance imaging data). The plurality of indicators may be identified based on scanned data. The plurality of indicators may be identified based on acoustic data. The data may be stored and retrieved from memory or may be received in real-time from an imaging device (e.g., MRI scanner) The plurality of indicators may be automatically identified by computer processing techniques and algorithms (e.g., trained algorithms or trained neural networks) or may be identified by a human and input by the human using a user input device (e.g., keyboard, touchscreen graphical user interface, computer mouse, trackpad, etc.).

The neuromodulation may include denervation or neurostimulation. The neuromodulation may include denervation or ablation of a basivertebral nerve, other intraosseous nerve, or a peripheral nerve.

In some embodiments, an unfavorable response would exclude subjects from certain treatment protocols (e.g., basivertebral nerve ablation procedure, discectomy, spinal fusion, facet denervation, peripheral neuromodulation). In some embodiments, a favorable response would qualify subjects for certain treatment protocols.

The method may further include categorizing multiple subjects based on objective scores calculated for the subjects. The categorizing could include identifying subjects likely to have a successful outcome from a particular treatment procedure and those subject likely not to have a successful outcome based on the objective scores. Subject-specific data (e.g., age, lifestyle factors, pain scores, images) could be used to facilitate the categorizing of subjects and to facilitate recommendation of any treatment protocols. The method may also include recommending treatment protocols based on the objective score. The method may further include treating the particular subject (e.g., if the calculated objective score is over a predetermined threshold).

At least a portion of any of the methods described above or elsewhere herein may be wherein at least a portion of the method is performed by application of artificial intelligence technology and techniques (e.g., trained machine learning or deep learning algorithms).

In accordance with several embodiments, a method of training a neural network to be used in determining whether or not a particular subject is a likely candidate for a basivertebral nerve ablation procedure is provided.

The method may include pre-processing a plurality of MRI images of at least a portion of a spine of a plurality of patients in order to make the MRI images more uniform for training. The method may also include identifying indicators of back pain that is likely to be successfully treated by the basivertebral nerve ablation procedure in at least some of the plurality of MRI images. The method may also include identifying images of the plurality of MRI images for which the patients were successfully treated by the basivertebral nerve ablation procedure. In some embodiments, the method may include comparing images prior to and after the basivertebral nerve ablation procedure treatment.

In accordance with several embodiments, a system for quantitatively predicting likelihood that a particular subject would respond favorably to basivertebral nerve ablation to treat chronic low back pain includes a server or computing system comprising one or more hardware processors configured to, upon execution of instructions stored on a non-transitory computer-readable storage medium: receive one or more images (e.g., MRIs) of at least a portion (e.g., lumbosacral region) of a spine of the particular subject, apply pre-processing imaging techniques to the one or more images in order to provide uniformity of the one or more images for feature detection, detect features from the one or more images to identify a plurality of indicators of back pain (e.g., chronic low back pain), quantify the identified plurality of indicators based on an extent of the plurality of indicators, and determine an objective score indicative of a likelihood that the particular subject would respond favorably to a basivertebral nerve ablation procedure based on the quantification of the plurality of indicators. The plurality of indicators may include, for example, bone marrow intensity changes and/or vertebral endplate defects or characteristics of vertebral endplate degeneration. The extent of the plurality of indicators may comprise a quantity, a severity, and/or a spatial assessment of the indicators.

In some embodiments, the one or more hardware processors are further configured to detect features from the one or more images (e.g., MRIs) to identify the plurality of indicators of back pain (e.g., chronic low back pain) by applying a trained neural network to the one or more images to automatically identify the plurality of indicators of back pain and/or to determine the objective score based on the identified plurality of indicators.

In some embodiments, the system includes an imaging scanner or system (such as an MRI scanner) from which the images can be retrieved and stored.

A non-transitory physical computer storage medium comprising computer-executable instructions stored thereon that, when executed by one or more processors, may be configured to implement a process including receiving one or more images (e.g., MRIs) of at least a portion of a spine of the particular subject, applying pre-processing imaging techniques to the one or more images, extracting features from the one or more images to identify a plurality of indicators of back pain (e.g., chronic low back pain), and determining an objective score indicative of a likelihood that the particular subject would respond favorably to basivertebral nerve ablation based on said extracting. The plurality of indicators include at least one of: (i) bone marrow intensity changes and (ii) vertebral endplate defects or characteristics of vertebral endplate degeneration.

The process may further include quantifying the identified plurality of indicators of back pain. Quantifying the identified plurality of indicators may include one or more of: determining a quantity of the bone marrow intensity changes and/or vertebral endplate defects, determining a level of extent of the bone marrow intensity changes and/or vertebral endplate defects, and quantifying identified fat fraction changes.

In some embodiments, extracting features comprises applying a trained neural network to the one or more images to automatically identify the plurality of indicators of back pain. In some embodiments, determining the objective score comprises applying a trained neural network to the one or more images to automatically calculate the objective score based on the extracting of features.

In accordance with several embodiments, a method of detecting and treating back pain of a subject includes identifying a candidate vertebral body for treatment based on a determination that the vertebral body exhibits one or more symptoms or defects associated with vertebral endplate degeneration and ablating a basivertebral nerve within the identified candidate vertebral body by applying a thermal treatment dose to a location within the vertebral body of at least 240 cumulative equivalent minutes (“CEM”) using a CEM at 43 degrees Celsius model or a comparable thermal treatment dose using another model, such as an Arrhenius model. The one or more symptoms associated with vertebral endplate degeneration or defects include pre-Modic change characteristics.

In some embodiments, the determination is based on images of the candidate vertebral body (e.g., MRI images, CT images, X-ray images, fluoroscopic images, ultrasound images). In some embodiments, the determination is based on obtaining biomarkers from the subject. The biomarkers may be obtained, for example, from one or more blood serum samples (e.g., blood plasma). The biomarkers may be obtained over an extended period of time (e.g., a period of days, weeks, or months) or at a single instance in time.

In accordance with several implementations, target, or candidate, vertebrae for treatment can be identified prior to treatment. The target, or candidate, vertebrae may be identified based on identification of various types of, or factors associated with, endplate degeneration and/or defects (e.g., focal defects, erosive defects, rim defects, corner defects, all of which may be considered pre-Modic change characteristics). For example, one or more imaging modalities (e.g., MRI, CT, X-ray, fluoroscopic imaging) may be used to determine whether a vertebral body or vertebral endplate exhibits active Modic characteristics or “pre-Modic change” characteristics (e.g., characteristics likely to result in Modic changes, such as Type 1 Modic changes that include findings of inflammation and edema or type 2 Modic changes that include changes in bone marrow (e.g., fibrosis) and increased visceral fat content). For example, images obtained via MRI (e.g., IDEAL MRI) may be used to identify (e.g., via application of one or more filters) initial indications or precursors of edema or inflammation at a vertebral endplate prior to a formal characterization or diagnosis as a Type 1 Modic change. Examples of pre-Modic change characteristics could include mechanical characteristics (e.g., loss of soft nuclear material in an adjacent intervertebral disc of the vertebral body, reduced disc height, reduced hydrostatic pressure, microfractures, focal endplate defects, erosive endplate defects, rim endplate defects, corner endplate defects, osteitis, spondylodiscitis, Schmorl's nodes) or bacterial characteristics (e.g., detection of bacteria that have entered an intervertebral disc adjacent to a vertebral body, a disc herniation or annulus tear which may have allowed bacteria to enter the intervertebral disc, inflammation or new capilarisation that may be caused by bacteria) or other pathogenetic mechanisms that provide initial indications or precursors of potential Modic changes or vertebral endplate degeneration or defects.

Accordingly, vertebral bodies may be identified as target candidates for treatment before Modic changes occur (or before painful symptoms manifest themselves to the patient) so that the patients can be proactively treated to prevent, or reduce the likelihood of, chronic low back pain before it occurs. In this manner, the patients will not have to suffer from debilitating lower back pain for a period of time prior to treatment. Modic changes may or may not be correlated with endplate defects and may or may not be used in candidate selection or screening. In accordance with several embodiments, Modic changes are not evaluated and only vertebral endplate degeneration and/or defects (e.g., pre-Modic change characteristics prior to onset or prior to the ability to identify Modic changes) are identified. Rostral and/or caudal endplates may be evaluated for pre-Modic changes (e.g., endplate defects that manifest before Modic changes that may affect subchondral and vertebral bone marrow adjacent to a vertebral body endplate).

In some implementations, a level of biomarker(s) (e.g., substance P, cytokines, high-sensitivity C-reactive protein, or other compounds associated with inflammatory processes and/or pain and/or that correlate with pathophysiological processes associated with vertebral endplate degeneration or defects (e.g., pre-Modic changes) or Modic changes such as disc resorption, Type III and Type IV collagen degradation and formation, or bone marrow fibrosis) may be obtained from a patient (e.g., through a blood draw (e.g., blood serum) or through a sample of cerebrospinal fluid) to determine whether the patient is a candidate for basivertebral nerve ablation treatment (e.g., whether they have one or more candidate vertebral bodies exhibiting factors or symptoms associated with endplate degeneration or defects (e.g., pre-Modic change characteristics)). Cytokine biomarker samples (e.g., pro-angiogenic serum cytokines such as vascular endothelial growth factor (VEGF)-C, VEGF-D, tyrosine-protein kinase receptor 2, VEGF receptor 1, intercellular adhesion molecule 1, vascular cell adhesion molecule 1) may be obtained from multiple different discs or vertebral bodies or foramina of the patient and compared with each other in order to determine the vertebral bodies to target for treatment. Other biomarkers may be assessed as well, such as neo-epitopes of type III and type IV pro-collagen (e.g., PRO-C3, PRO-C4) and type III and type IV collagen degradation neo-epitopes (e.g., C3M, C4M).

In some implementations, samples are obtained over a period of time and compared to determine changes in levels over time. For example, biomarkers may be measured weekly, bi-monthly, monthly, every 3 months, or every 6 months for a period of time and compared to analyze trends or changes over time. If significant changes are noted between the biomarker levels (e.g., changes indicative of endplate degeneration or defects (e.g., pre-Modic change characteristics) or Modic changes, as described above), treatment may be recommended and performed to prevent or treat back pain. Biomarker levels (e.g., substance P, cytokine protein levels, PRO-C3, PRO-C4, C3M, C4M levels) may be measured using various in vivo or in vitro kits, systems, and techniques (e.g., radio-immunoassay kits/methods, enzyme-linked immunosorbent assay kits, immunohistochemistry techniques, array-based systems, bioassay kits, in vivo injection of an anticytokine immunoglobulin, multiplexed fluorescent microsphere immune-assays, homogeneous time-resolved fluorescence assays, bead-based techniques, interferometers, flow cytometry, etc.). Cytokine proteins may be measured directly or indirectly, such as by measuring mRNA transcripts.

The identification of pre-Modic change characteristics may involve determining a quantitative or qualitative endplate score based on severity, extent, and/or quantity of the identified pre-Modic change characteristics (e.g., vertebral endplate defects) and vertebrae having a quantitative endplate score above a threshold may be deemed as potential candidates for treatment (e.g., basivertebral nerve ablation). The pre-Modic change characteristics may be combined with age, gender, body mass index, bone mineral density measurements, back pain history, and/or other known risk factors for vertebral endplate degeneration or defects (such as smoking, occupational or recreational physical demands or situations) in identifying candidate patients and/or candidate vertebral bodies for treatment (e.g., basivertebral nerve ablation).

In accordance with several embodiments, a method of detecting and treating back pain of a subject includes obtaining images of a vertebral body of the subject and analyzing the images to determine whether the vertebral body exhibits one or more symptoms associated with a pre-Modic change. The method also includes modulating (e.g., ablating, denervating, stimulating) an intraosseous nerve (e.g., basivertebral nerve) within the vertebral body if it is determined that the vertebral body exhibits one or more symptoms associated with a pre-Modic change.

The images may be obtained, for example, using an MRI imaging modality, a CT imaging modality, an X-ray imaging modality, an ultrasound imaging modality, or fluoroscopy. The one or more symptoms associated with a pre-Modic change may comprise characteristics likely to result in Modic changes (e.g., Type 1 Modic changes, Type 2 Modic changes). The one or more symptoms associated with a pre-Modic change may comprise initial indications or precursors of edema or inflammation at a vertebral endplate prior to a formal characterization or diagnosis as a Modic change. The one or more symptoms may include edema, inflammation, and/or tissue change within the vertebral body or along a portion of a vertebral endplate of the vertebral body. Tissue changes may include tissue lesions or changes in tissue type or characteristics of an endplate of the vertebral body and/or tissue lesions or changes in tissue type or characteristics of bone marrow of the vertebral body. The one or more symptoms may include focal defects, erosive defects, rim defects, and corner defects of a vertebral endplate of the vertebral body.

Spinal treatment procedures may include modulation of nerves within or surrounding bones of the spine (e.g., vertebral bodies). The terms “modulation” or “neuromodulation”, as used herein, shall be given their ordinary meaning and shall also include ablation, permanent denervation, temporary denervation, disruption, blocking, inhibition, electroporation, therapeutic stimulation, diagnostic stimulation, inhibition, necrosis, desensitization, or other effect on tissue. Neuromodulation shall refer to modulation of a nerve (structurally and/or functionally) and/or neurotransmission. Modulation is not necessarily limited to nerves and may include effects on other tissue, such as tumors or other soft tissue.

The particular spinal neuromodulation procedure to be performed may include denervating (e.g., ablating) the basivertebral nerve within the vertebral body may include applying energy (e.g., radiofrequency energy, ultrasound energy, microwave energy) to a target treatment region within the vertebral body sufficient to denervate (e.g., ablate, electroporate, molecularly dissociate, necrose) the basivertebral nerve using a radiofrequency energy delivery device. The denervating may alternatively or additionally include applying an ablative fluid (e.g., steam, chemical, cryoablative fluid) to a target treatment region within the vertebral body.

Any of the method steps described herein may be performed by one or more hardware processors (e.g., of a server) by executing program instructions stored on a non-transitory computer-readable medium.

Several embodiments of the invention have one or more of the following advantages: (i) increased treatment accuracy; (ii) increased efficacy results; (iii) increased efficiency; (iv) increased patient satisfaction; (v) increased number of people receiving the particular back pain treatment procedure that would not have been previously identified; and/or (vi) reduction in patients treated in which the particular back pain treatment procedure would not be successful due to the back pain originating from other sources.

For purposes of summarizing the disclosure, certain aspects, advantages, and novel features of embodiments of the disclosure have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the disclosure provided herein. Thus, the embodiments disclosed herein may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught or suggested herein without necessarily achieving other advantages as may be taught or suggested herein.

The methods summarized above and set forth in further detail below describe certain actions taken by a practitioner; however, it should be understood that they can also include the instruction of those actions by another party. Thus, actions such as, for example, “applying thermal energy” include “instructing the applying of thermal energy.” Further aspects of embodiments of the disclosure will be discussed in the following portions of the specification. With respect to the drawings, elements from one figure may be combined with elements from the other figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Several embodiments of the disclosure will be more fully understood by reference to the following drawings which are for illustrative purposes only:

FIG. 1 illustrates an embodiment of a computing environment including a quantitative patient candidate diagnostics (QPCD) system that can enable clinicians to quantitatively analyze patient candidates for a basivertebral nerve ablation procedure.

FIGS. 2-4 illustrate embodiments of a process for generating an objective or quantitative prediction of likelihood that a patient candidate will respond favorably to a basivertebral nerve ablation procedure or other treatment.

FIGS. 5, 6A-6D and 7 illustrate examples of pre-processing and/or feature extraction steps to facilitate identification and quantitative assessment of a plurality of indicators of back pain.

FIG. 8 illustrates a schematic flow diagram of an embodiment of training a neural network and then using the neural network to perform the quantitative prediction of likelihood that a patient candidate will respond favorably to a basivertebral nerve ablation procedure or other treatment.

DETAILED DESCRIPTION Introduction

Back pain (e.g., chronic low back pain) may be caused by many sources, including vertebral endplate defects or degeneration, bone marrow intensity changes such as Modic changes, ligament sprains, facet joint pain, muscle strain, muscle atrophy, spinal tendon injury, spinal nerve compression, herniated discs, slipped discs, degenerative disc disease, sacroiliac joint dysfunction, bacterial or fungal infection, vertebral fractures, osteoporosis, and/or spinal tumors. It can be difficult for clinicians to identify an exact source of the back pain with confidence and reliable accuracy simply by visually inspecting images obtained from one or more imaging modalities and/or by reviewing subjective patient pain scores (e.g., Oswestry Disability Index (“ODI”) scores or Visual Analog Score (“VAS”) pain scores, quality of life measures, patient reported outcome measures). As a result, sometimes patients with back pain (e.g., chronic low back pain) are treated using a particular procedure that does not successfully reduce the back pain of the patient because the particular procedure does not effectively treat the actual source of the back pain, or does not treat all the actual sources of the back pain.

For example, the particular back pain treatment procedure may be a basivertebral nerve ablation procedure designed to treat back pain (e.g., chronic low back pain) originating from one or more vertebral bodies or vertebral endplates and the actual source of pain may be, or also include, discogenic pain originating from one or more intervertebral discs that may not be effectively treated by the basivertebral nerve ablation procedure. As another example, patients may receive a back pain treatment procedure intended to treat discogenic pain or pain originating from sources other than from one or more vertebral bodies or vertebral endplates when the actual source of pain originates from one or more vertebral bodies or vertebral endplates. Accordingly, clinicians may perform procedures that are not effective, or not successful, and patients may experience ongoing pain and reduced satisfaction that may result in poor feedback or patient reviews for the particular clinician or hospital or treatment center or company providing the technology used for the procedure.

In accordance with several embodiments, systems and methods disclosed herein provide a more reliable prediction of a particular source or type of back pain (e.g., chronic low back pain) that may be effectively treated by a particular back pain treatment procedure (e.g., basivertebral nerve ablation procedure). The systems and methods disclosed herein may also advantageously provide an increase in the number of patients identified as likely candidates for the particular back pain treatment procedure (e.g., basivertebral nerve ablation procedure) that may not have been identified previously based on image visualization by clinicians or subjective or qualitative factors or input from patients. The prediction may involve generation (e.g., fully or partially-automated automated calculation) of an objective or quantitative score, value, or other output based on a combination (e.g., weighted combination) of indicators of the particular source of the type of back pain that may be effectively treated by a particular back pain treatment procedure (e.g., basivertebral nerve ablation procedure). Basing the prediction on multiple indicators may provide enhanced accuracy, reliability and confidence and reduce false positives and false negatives. In addition, the percentage of successful treatments for the particular back pain treatment procedure (e.g., basivertebral nerve ablation procedure) may advantageously be increased, resulting in increased patient satisfaction and reduced costs. The systems and methods disclosed herein may also enable clinicians to tailor or adjust parameters (e.g., positioning, duration, targets) of the particular back pain treatment procedure (e.g., basivertebral nerve ablation procedure) to more effectively treat the actual source of the back pain (e.g., chronic low back pain).

Example QPCD System

FIG. 1 illustrates an embodiment of a computing environment 100 for providing clinicians with access to a QPCD system 120 to determine patient candidates likely to have pain stemming from one or more vertebral bodies or vertebral endplates and thus likely to respond favorably to a spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure, such as the Intracept® basivertebral nerve ablation procedure provided commercially by Relievant Medsystems, Inc.) that targets that particular source of back pain (e.g., chronic low back pain). In an embodiment, the QPCD system 120 determines a quantitative assessment (e.g., score, value, or other output) of a patient's likelihood of responding favorably to the spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure) based, at least in part, on analyzing a plurality of indicators identified from images of at least a portion of the patient's spine obtained using one or more imaging modalities (e.g., MRI, CT, SPECT, X-ray, etc.). The computing environment 100 can include clinician systems 108 that can access the QPCD system 120, which may include one or more modules to determine the patient's likelihood of back pain originating from a particular source (e.g., one or more vertebral endplates or vertebral bodies) and thus likelihood of the patient responding favorably to a particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure).

The QPCD system 120 can include an image retriever module 122 that can retrieve images corresponding to scans of at least a portion of a spine (e.g. lumbar region, sacral region, thoracic region, cervical region, or combinations of two or more of these spinal regions) of a particular patient or multiple subjects. In an embodiment, the image retriever 122 can receive raw images directly from an imaging scanner 106 (e.g., MRI scanner). In other embodiments, the image retriever 122 can receive images from a PACS (Picture Archiving and Communication System) repository 102. The image retriever module 122 can also receive images from a storage medium such as a compact disc (CD), a portable hard drive, cloud storage, servers, or other storage database or storage medium, etc. The PACS repository 102 may store images, for example, in a DICOM (Digital Imaging and Communication in Medicine) format. The PACS repository 102 may also include other non-image data regarding patients (e.g., age, gender, body mass index, bone mineral density measurements, pain scores, quality of life measures, patient-reported outcomes, whether the patients received spinal neuromodulation therapy or not, and whether or not the therapy was successful). The image retriever module 122 can also receive images of different formats (e.g. jpeg, png, pdf, bmp, CT scanner raw files, MRI raw files, PET raw files, x-ray raw files, etc.). In an embodiment, the image retriever module 122 retrieves images from the PACS repository 102 or imaging scanners wirelessly over a network 104. In another embodiment, the image retriever module 122 retrieves images through a local wired or integrated connection. The image retriever module 122 may receive the images from the PACS repository 102 in response to an input from the clinician system 108.

The QPCD system 120 can include an image processing module 124 to perform pre-processing and/or analysis (e.g., feature extraction, or detection) of the images retrieved by the image retriever module 122. The image processing module 124 can process the images and identify one or more indicators of back pain stemming from one or more vertebral bodies or vertebral endplates from the images as described in more detail below. The indicators can include one or more of bone marrow intensity changes, vertebral endplate defects or degeneration, paraspinal muscle tissue characteristics (e.g., multifidus muscle atrophy), bone turnover, intervertebral disc calcification indicators, etc. The image processing module 124 can pre-process received images (e.g., by performing rotation, sizing changes, contrast changes, image quality enhancement, or other image processing and clean-up techniques) to prepare the images for feature extraction, or feature detection to identify the indicators. The image processing module 124 can also perform feature extraction, or feature detection, to identify the one or more indicators of back pain arising from one or more vertebral bodies or vertebral endplates from the images. The feature extraction may include an identification (e.g., alphanumeric text label) of each vertebral level shown in the image (such as shown in FIG. 5 ). The image processing module 124 may use information obtained from one image to process another image for the same patient or future patients. The image processing module 124 may incorporate previously-trained neural networks to perform pre-processing and/or feature extraction on the images.

The QPCD system 120 may also include a quantifier/score calculator module 126 to quantify the plurality of indicators identified by the image processing module 124 and to generate an objective or quantitative score, value, or other output indicative of likelihood that the patient would favorably respond to a particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure) that targets a source of back pain correlated with the plurality of indicators based on the objective or quantitative score, value, or other output. In some embodiments, the quantifier/score calculator module 126 may generate a binary output indicating a Yes or No output or recommendation to proceed with the particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure) based on the objective or quantitative score or other value. The quantifier/score calculator module 126 may also include post-processing checks intended to provide increased confidence in the score or value, or in the binary Yes/No output (e.g., to reduce false positives or false negatives). For example, the objective or quantitative score, value, or other output may be based on analysis of a combination (e.g., weighted combination) of one or more indicators (e.g., first-tier indicators such as bone marrow intensity changes and/or vertebral endplate defects or degeneration) and the post-processing checks may be based on analysis of one or more additional indicators (e.g., second-tier indicators such as paraspinal muscle characteristics, bone turnover determined from SPECT imaging). The quantitative scores or other values and/or the binary output can be stored in the patient data repository 140 or in the PACS repository 102 along with other data for the patient. The scores or other quantitative values and/or the binary output can also be transmitted over a wired or wireless network to a clinician system 108. The quantifier/score calculator module 126 may also apply previously-trained algorithms or neural networks.

The image processing module 124 may store analyzed images in a patient data repository 140 or transmit it back to the PACS repository 102. In some embodiments, the image processing module 124 may include internal checks to ensure that the images correspond to a spine or portion of a spine. The user interface module 128 can interact with one or more other modules of the QPCD system 120 to generate one or more graphical user interfaces. In some embodiments, the graphical user interfaces can be one or more web pages or electronic documents. The user interface module 128 can also receive data such as patient information from the clinician system(s) 108. In some instances, the user interface module 128 may receive commands from the clinician system(s) 108 to initiate one or more functionalities of the QPCD system 120.

The QPCD system 120 can be implemented in computer hardware and/or software. The QPCD system 120 can execute on one or more computing devices, such as one or more physical server computers. In implementations where the QPCD system 120 is implemented on multiple servers, these servers can be co-located or can be geographically separate (such as in separate data centers). In addition, the QPCD system 120 can be implemented in one or more virtual machines that execute on a physical server or group of servers. Further, the QPCD system 120 can be hosted in a cloud computing environment, such as in the Amazon Web Services (AWS) Elastic Compute Cloud (EC2) or the Microsoft® Windows® Azure Platform. The QPCD system 120 can also be integrated with scanners 106 through software or hardware plug-in or an API (application programming interface). In some embodiments, the clinician systems 108 may implement some or all of the modules of the QPCD system 120. For instance, the clinician systems 108 may implement the user interface generator module 128, while the rest of the modules are implemented remotely on a server. In other embodiments, a plugin to the QPCD system 120 may be installed on a third party tool. The QPCD system 200 can include multiple engines or modules for performing the processes and functions described herein, such as the modules described above. The engines or modules can include programmed instructions for performing processes as discussed herein. The programming instructions can be stored in a memory. The programming instructions can be implemented in C, C++, JAVA, or any other suitable programming languages. In some embodiments, some or all of the portions of the QPCD system 120 including the engines or modules can be implemented in application specific circuitry such as ASICs and FPGAs. While shown as separate engines or modules, the functionality of the engines or modules as discussed herein is not necessarily required to be separated.

The clinician systems 108 can remotely access the QPCD system 120 on these servers through the network 104. The clinician systems 108 can include thick or thin client software that can access the QPCD system 120 on the one or more servers through the network 104. The network may be a local area network (LAN), a wide area network (WAN), such as the Internet, combinations of the same, or the like. For example, the network 104 can include a hospital or other institution's private intranet, the public Internet, or a combination of the same. In some embodiments, the user software on the clinician system 108 can be a browser software or other application software. The clinician system 108 can access the QPCD system 120 through the browser software or other application software.

In general, the clinician systems 108 can include any type of computing device capable of executing one or more applications and/or accessing network resources. For example, the clinician systems 108 can be desktops, laptops, netbooks, tablet computers, smartphones, smartwatches, augmented reality wear, PDAs (personal digital assistants), servers, e-book readers, video game platforms, television set-top boxes (or simply a television with computing capability), a kiosk, combinations of the same, or the like. The clinician systems 108 include software and/or hardware for accessing the QPCD system 120, such as a browser or other client software.

Example Quantitative Prediction Processes

FIG. 2 illustrates an embodiment of a process 200 for generating an objective or quantitative prediction of likelihood that a patient candidate will respond favorably to a particular spinal neuromodulation procedure (e.g., a basivertebral nerve ablation procedure) intended to target a particular source of back pain (e.g., back pain originating from one or more vertebral bodies or vertebral endplates). The objective or quantitative prediction can be a numerical, graphical, or textual indicator (or combination of the same). For example, the objective or quantitative prediction can include a percentage, a score on a scale, a binary Yes or No, and/or a color. The quantitative prediction process 200 can be implemented by the QPCD system 120 described above. For illustrative purposes, the quantitative prediction process 200 will be described as being implemented by components of the computing environment 100 of FIG. 1 . The entire process 200 or portions of the process 200 may be automated by execution of stored program instructions stored on a non-transitory computer-readable medium by one or more hardware processors.

The quantitative prediction process 200 beings at block 202 with receiving images of a patient candidate (e.g., from the PACS 102 or from imaging scanners 106). The image retriever module 122 can receive image data corresponding to MRI, CT, SPECT, PET, X-ray or other imaging scans of at least portions of the patient's spine. The MRI image data may include T1-weighted MRI images, T2-weighted MRI images, fat-suppression MRI images, UTE MRI sequenced images, IDEAL MRI sequenced images, fast spin echo MRI images, T1ρ-weighted images, and/or other MRI images obtained using other MRI sequences, pulsing, weighting, or techniques. The received images may include one or more regions of the patient's spine (e.g. lumbar region, sacral region, thoracic region, cervical region, or combinations of two or more of these spinal regions). The images may comprise sequential images over a period of time or images at a single point in time.

At Block 204, the QPCD system 120 can analyze the received images to identify and quantify one indicator or multiple indicators of back pain (e.g., vertebral endplate defects or degeneration, bone marrow intensity changes, paraspinal muscle tissue characteristics (e.g., multifidus muscle atrophy), active bone turnover, intervertebral disc calcification indicators, vertebral fat fraction) in or from the images. The indicators of back pain may be indicators correlated to back pain stemming from one or more vertebral bodies or vertebral endplates and/or from one or more adjacent intervertebral discs. For example, the image processing module 124 can perform image processing technique to automatically identify, or detect, the one or more indicators (e.g., through feature extraction) and the quantifier/score calculator module 126 can analyze (e.g., quantify) the identified one or more indicators. The quantifier/score calculator module 126 can then generate an objective prediction (e.g., quantitative score) of likelihood that the patient has pain stemming from one or more vertebral bodies or vertebral endplates and will respond favorably to a spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure) at Block 206.

In some embodiments, only indicators of back pain known to correlate with pain stemming from one or more vertebral bodies or vertebral endplates are identified and assessed and indicators of discogenic back pain (pain originating from the intervertebral disc) or other pain sources are not identified or assessed. The indicators may be identified or determined and/or objective scores may be generated or calculated by application of trained algorithms or trained neural networks.

The QPCD system 120 may optionally generate a confidence level or perform an additional verification step at Block 208 to reduce false positives or negatives in the objective prediction (e.g., quantitative score or binary YES/NO output). The verification or confidence level generation step may involve identification and/or quantification of one or more additional indicators (e.g., indicators known to have a strong correlation or sensitivity with) of a particular source of back pain (e.g., chronic low back pain stemming from one or more vertebral bodies or vertebral endplates) not used in the previous steps. For example, the multiple indicators identified and quantified in the previous steps may include vertebral endplate defects or degeneration and/or bone marrow intensity changes, whereas the one or more indicators used in the verification or confidence level generation step at Block 208 may include paraspinal muscle tissue characteristics (e.g., multifidus muscle characteristics), active bone turnover, intervertebral disc calcification, or other indicators.

In some embodiments, the indicators used at Blocks 204 and 206 may be considered first-tier or more reliable/accurate indicators of the particular source of back pain and the indicators used at Block 208 may be considered second-tier indicators correlated to the particular source of back pain. In other embodiments, the indicators used to determine the quantitative score or other output may be more well accepted at the time by clinicians as correlating to the particular source of back pain (e.g., chronic low back pain originating from one or more vertebral bodies or vertebral endplates). The indicators identified and quantified at Block 208 may be identified based on the same images as in Blocks 204 and 206 or based on different images (e.g., SPECT images, CT images, different MRI images). In an embodiment, the images used at Blocks 204 and 206 are only MRI images but may constitute different types of MRI images (e.g., T1-weighted images, T2-weighted images, fat-suppressed images, UTE images, IDEAL images). In some embodiments, the first-tier and second-tier indicators are both used to determine the quantitative score or other output.

FIG. 3 illustrates another embodiment of a process 300 for generating an objective or quantitative prediction of likelihood that a patient candidate will respond favorably to a spinal neuromodulation procedure (e.g., a basivertebral nerve ablation procedure). As with quantitative prediction process 200, the quantitative prediction process 300 can be implemented by the QPCD system 120 described above. For illustrative purposes, the quantitative prediction process 300 will be described as being implemented by components of the computing environment 100 of FIG. 1 . The entire process 300 or portions of the process 300 may be automated by execution of stored program instructions stored on a non-transitory computer-readable medium by one or more hardware processors. Any of the steps of the process 300 may include application of trained algorithms or trained neural networks.

At Block 302, the QPCD system 120 (e.g., image retriever module 122) receives images of a patient candidate for a spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure). The images may correspond to MRI, CT, SPECT, PET, X-ray or other imaging scans of the patient's spine. The MRI images may include T1-weighted MRI images, T2-weighted MRI images, fat-suppressed MRI images, UTE MRI images, and/or IDEAL MRI images. The received images may include one or more regions of the patient's spine (e.g. lumbar region, sacral region, thoracic region, cervical region, or combinations of two or more of these spinal regions). The images may comprise sequential images over a period of time or images at a single point in time.

At Block 304, the image processing module 124 may apply pre-processing to the images. The pre-processing may involve analog or digital image processing techniques. The pre-processing may include rotating, cropping, enlarging, reducing, removing noise, segmenting, smoothing, contrast or color enhancing, and/or other image processing techniques. The pre-processing may also include spatial orientation identification, vertebral level identification, general anatomical feature identification, and/or the like. In some embodiments, the pre-processing may be performed by running the images through a previously-trained neural network trained to clean up, enhance, reconstruct, or otherwise improve the quality of images, such as noisy MRI images.

At Block 306, the image processing module 124 may perform feature extraction on the pre-processed images. Feature extraction may include spatial orientation identification, vertebral level identification, general anatomical feature identification, and/or the like if not performed in the pre-processing. Feature extraction may also include identification of indicators of back pain in the images (e.g., vertebral endplate defects or degeneration, bone marrow intensity changes, paraspinal muscle tissue characteristics (e.g., multifidus muscle atrophy), bone turnover, vertebral bone marrow fat fraction, intervertebral disc calcification, etc.).

The QPCD system 120 may then analyze the extracted features at Block 308. The analysis may include applying one or more rules to the extracted features to assess (e.g., quantify) identified indicators of back pain and the likelihood that the patient with the identified indicators would respond favorably to a particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure).

The analysis of vertebral endplate defects or degeneration may include spatial and quantification analyses. The spatial analysis may include, for example, identification of the location(s) or position(s) along the vertebral endplate where the defects or degeneration occur. The analysis of vertebral endplate defects or degeneration may include, for example, identifying various subclassifications of defects (e.g., focal defects, erosive defects, rim defects, corner defects), identifying defects to a normal continuous lining of a vertebral endplate, identifying irregularities in the endplate lining, assessing an amount, or quantity, of defects, assessing an extent or severity of the defects (e.g., width, depth, total area or volume, percentage of whole), evaluating contour profiles of vertebral endplates (e.g., jaggedness, depth), identifying the defects as being a particular phenotype subtype of vertebral endplate defect. Contour profiles may be developed, for example, through hypo- and hyper-signal identification on T1-weighted or T2-weighted images.

The analysis of bone marrow intensity changes may include a classification of the changes as Type 1 or Type 2 Modic changes based on conventional Modic change classification schemes. The analysis of bone marrow intensity changes may also include a spatial and/or extent or severity of change analysis. For example, the analysis may identify locations where the bone marrow intensity changes occur within a vertebral body and/or an extent (height, volume, position) of the bone marrow intensity changes. Annular-nuclear border bone marrow intensity changes may be more significant than bone marrow intensity changes in a center of a vertebral body, for example, or vice-versa. In some embodiments, the Modic changes may be classified using T1-weighted, T2-weighted, or fat-suppression MRI images. For example, Type 1 Modic changes may be identified as white swelling or inflammation on T2-weighted MRI images and less bright spots on T1-weighted MRI images. Type 2 Modic changes may be identified as light spots on both T1- and T2-weighted MRI images. In some embodiments, the analysis of bone marrow intensity changes may incorporate use of UTE MRI sequences or IDEAL sequences.

In some embodiments, the analysis of bone marrow intensity changes may include assessment of vertebral fat fraction. Vertebral fat fraction (e.g. conversion of water to fat in bone marrow) may comprise analysis of IDEAL MRI images. Bone marrow intensity changes may be identified in both the vertebral body and in one or more adjacent vertebral endplates. Bone marrow intensity changes may include, for example, bone marrow edema, bone marrow inflammation, bone marrow lesions, and/or conversion of normal red haemopoietic bone marrow into yellow fatty marrow, which can be identified from the received images.

Bone marrow intensity changes may also comprise pre-Modic change characteristics that provide initial indications or precursors of edema or inflammation at a vertebral endplate prior to a formal characterization or diagnosis as a Type 1 Modic change. Examples of pre-Modic change characteristics could include mechanical characteristics (e.g., loss of soft nuclear material in an adjacent intervertebral disc of the vertebral body, reduced disc height, reduced hydrostatic pressure, microfractures, fissures, spondylodiscitis, Schmorl's nodes, osteitis) or bacterial characteristics (e.g., detection of bacteria that have entered an intervertebral disc adjacent to a vertebral body, a disc herniation or annulus tear which may have allowed bacteria to enter the intervertebral disc, inflammation or new capilarisation that may be caused by bacteria) or other pathogenetic mechanisms that provide initial indications or precursors of potential Modic changes. Rostral and/or caudal endplates may be evaluated for pre-Modic changes (e.g., endplate defects that manifest before Modic changes that may affect subchondral and vertebral bone marrow adjacent to a vertebral body endplate).

After the analysis of extracted features at Block 308, the QPCD system 120 (e.g., quantifier/score calculator module 126) may generate an objective prediction (e.g., quantitative score or other output) of likelihood that the patient will respond favorably to a spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure) based on the analysis of the extracted features, similar as described in connection with Block 206 of quantitative prediction process 200. The output generated may be a binary YES or NO output as to whether the patient is likely to respond favorably to the spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure). The output may be based on analysis of a combination (e.g., weighted combination) of two, three, four, or more than four indicators, which may include only first-tier indicators or both first-tier indicators and second-tier indicators.

The quantitative prediction process 300 may optionally include post-processing refinement at Block 312. The post-processing refinement may function, for example, as a check to reduce false positives or false negatives or to provide increased confidence in the quantitative prediction. The post-processing refinement may include identification and analysis of one or more additional indicators of back pain, as described in connection with Block 208 of quantitative prediction process 200. The post-processing refinement may provide an additional level of confidence in the determination at Block 310. In some embodiments, the post-processing refinement is not performed. For example, the post-processing refinement may not be performed if the quantitative score or other value is above a certain predetermined threshold so as to increase processing time if post-processing refinement is not needed or desired.

As described above in connection with Block 208 of quantitative prediction process 200, the additional indicators identified and analyzed in the post-processing refinement at Block 312 may include paraspinal muscle tissue characteristics (e.g., multifidus muscle atrophy) may include analysis of a cross-sectional area (diameter, size) of the atrophy based on images and/or an analysis of fat fraction within the muscle tissue (e.g., percentage or ratio). The paraspinal muscle tissue characteristics may be identified, for example, in T1-weighted MRI images and/or T2-weighted fast spin-echo MRI images. The analysis and quantification of paraspinal muscle tissue characteristics may include spatial analysis (e.g., position or location of fatty atrophic changes in muscle composition). For example, fatty atrophic changes in muscle composition of paraspinal muscle tissue (e.g., multifidus muscle tissue) may be identified as high intensity areas medial and/or deep along a multifidus muscle myofascial sheath. The analysis and quantification of paraspinal muscle tissue characteristics may include quantification of an extent or severity of the changes in muscle tissue characteristics (e.g., extent of fatty infiltration measured as a percentage of a total cross-sectional area of muscle tissue).

The additional indicators identified and analyzed in the post-processing refinement at Block 312 may also include detection of active bone turnover (inflammatory response) based on SPECT images. For example, inflamed bone turns over faster than normal bone and may be identified and quantified. Patient candidates having vertebral bodies with active bone turnover may be more likely to respond favorably to a particular spinal neuromodulation procedure (e.g., basivertebral nerve procedure).

In some embodiments, the additional indicators (e.g., second-tier indicators) could include indicators of discogenic pain stemming from one or more vertebral discs (e.g., disc calcification, biochemical composition (e.g., proteoglycan and collagen content) or morphology of the disc, annular tears, Pfirrman grade scores, and/or the like). Such additional indicators may be used, for example, if the particular spinal neuromodulation procedure (e.g., basivertebral nerve procedure) is likely to be effective in treating discogenic back pain in addition to pain originating from one or more vertebral bodies or vertebral endplates. However, in some embodiments, indicators of discogenic pain (or at least only of discogenic pain) are not identified or analyzed.

In some embodiments, the additional indicators could include indicators (e.g., biomarkers) that may not be identified from images. The biomarkers may comprise, for example, substance P, cytokines, high-sensitivity C-reactive protein, or other compounds associated with inflammatory processes and/or pain and/or that correlate with pathophysiological processes associated with vertebral endplate degeneration or defects (e.g., pre-Modic changes) or Modic changes such as disc resorption, Type III and Type IV collagen degradation and formation, or bone marrow fibrosis). The biomarkers may be obtained from a patient (e.g., through a blood draw (e.g., blood serum) or through a sample of cerebrospinal fluid). Cytokine biomarker samples (e.g., pro-angiogenic serum cytokines such as vascular endothelial growth factor (VEGF)-C, VEGF-D, tyrosine-protein kinase receptor 2, VEGF receptor 1, intercellular adhesion molecule 1, vascular cell adhesion molecule 1) may be obtained from multiple different discs or vertebral bodies or foramina of the patient and compared with each other in order to determine the vertebral bodies to target for treatment. Other biomarkers may be assessed as well, such as neo-epitopes of type III and type IV pro-collagen (e.g., PRO-C3, PRO-C4) and type III and type IV collagen degradation neo-epitopes (e.g., C3M, C4M).

Biomarkers may include genetic markers, products of gene expression, autoantibodies, cytokine/growth factors, proteins or enzymes (such as heat shock proteins), and/or acute phase reactants. Biomarkers may include compounds correlated to back pain, such as inflammatory cytokines, Interleukin-1-beta (IL-1-beta), interleukin-1-alpha (IL-1-alpha), interleukin-6 (IL-6), IL-8, IL-10, IL-12, tumor necrosis factor-alpha (TNF-alpha), granulocyte-macrophage colony stimulating factor (GM-CSF), interferon gamma (INF-gamma), and prostaglandin E2 (PGE2). Biomarkers may also be indicative of presence of tumor cells or tissue if tumor tissue is being targeted by the particular procedure. Biomarkers may be found in blood serum/plasma, urine, synovial fluid, tissue biopsy, foramina, intervertebral discs, cerebrospinal fluid, or cells from blood, fluid, lymph node, and/or tissue. In some embodiments, the biomarkers can be indicators identified from images.

FIG. 4 illustrates an embodiment of a specific implementation of a process 400 for generating an objective or quantitative prediction of likelihood that a patient candidate has back pain arising from one or more vertebral bodies or vertebral endplates and thus will likely respond favorably to a particular spinal neuromodulation procedure (e.g., a basivertebral nerve ablation procedure). The entire process 400 or portions of the process 400 may be automated by execution of stored program instructions stored on a non-transitory computer-readable medium by one or more hardware processors. Any of the steps of the process 300 may include application of trained algorithms or trained neural networks. The quantitative prediction process 400 first includes identifying vertebral endplate defects and/or degeneration at Block 402. The quantitative prediction process 400 then includes identifying bone marrow intensity changes at Block 404. It should be appreciated that these two steps may be performed in the opposite order. The identifying steps at Blocks 402 and 404 may be performed, for example, by the image processing module 124 by applying pre-processing and feature extraction techniques, such as described above in connection with FIGS. 2 and 3 . Turning to Block 406, the quantitative prediction process 400 then includes analyzing the defects and/or changes identified at Blocks 402 and 406. At Block 408, the quantitative prediction process 400 includes generating an objective prediction of likelihood that a particular patient candidate would have a favorable response to a particular spinal neuromodulation procedure (e.g., a basivertebral nerve ablation procedure). The analyzing and generating steps of Blocks 406 and 408 may be performed, for example, by the quantifier/score calculator module 126, such as described above in connection with FIGS. 2 and 3 .

Any of the quantitative prediction processes 200, 300, 400 may further include displaying the quantitative score, value or other output (e.g., binary YES/NO output) on a display to be visible by a clinician (e.g., display on a clinician system 108). The display of the output may be executed or carried out by the user interface module 128 of the QPCD system 120. A clinician may decide whether or not to move forward with a procedure on a particular patient based on the output. Treatment protocols may also be adjusted based on the output.

FIGS. 5, 6A-6D and 7 illustrate examples of pre-processing and/or feature extraction steps that may be performed by the QPCD system 120 to facilitate identification and quantitative assessment of a plurality of indicators of back pain. FIG. 5 shows an example of identification of vertebral levels on an MRI image of a lumbosacral region of a patient's spine (L1-52 levels identified). The identification may include, for example, alphanumeric textual labels, as shown in FIG. 5 . FIGS. 6A-6D show examples of identification of vertebral endplate defects or degeneration on various MRI images. The white arrows overlaid on the images identify the vertebral endplate defects. FIG. 6A is a normal healthy body and so no indicators are identified. FIG. 6B identifies a focal defect of a vertebral endplate. FIG. 6C identifies a corner defect of a vertebral endplate. FIG. 6D identifies erosive defects of a vertebral endplate. FIG. 7 shows an example of bone marrow intensity changes on an MRI image. The bone marrow intensity changes are identified by the white arrows overlaid on the images. Bone marrow intensity changes may appear as hyperintense tissue regions and/or hypointense tissue regions depending on types of relaxation or MRI signals and sequencing used (e.g., T1-weighted or T2-weighted MRI signals).

The vertebral endplate defects and/or bone marrow intensity changes may be identified by the image processing module 124 of the QPCD system 120 as described above. For example, the vertebral endplate defects and/or bone marrow intensity changes may be identified and extracted as features to be analyzed using image processing and feature extraction, or feature detection, techniques. The vertebral endplate defects and/or bone marrow intensity changes may be identified for example, by pixel/voxel color value comparison techniques, pixel/voxel signal intensity comparison, cluster analysis techniques, image comparison techniques by comparing with an image of a normal healthy patient without back pain indicators, etc.

Training of Neural Networks

In accordance with several embodiments, one or more steps of the processes described herein can be performed using machine learning techniques (e.g., using a trained artificial neural network that involves deep learning algorithms). The machine learning or deep learning algorithms may be trained using supervised or unsupervised training. The processes disclosed herein can employ machine learning modeling along with signal processing techniques to analyze images to identify indicators of back pain and determine quantitative predictions or scores, such as discussed above. Use of machine learning may advantageously increase reliability or accuracy of predictions, may reduce the time to identify patients likely to favorably respond to a particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure), and reduce false positive predictions based on human error. In accordance with several embodiments, by applying machine learning algorithms to large quantities of images of healthy subjects without back pain and images of patients having back pain, reliably accurate and extremely quick identification of patient candidates likely to respond favorably to a particular quantitative prediction of likelihood spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure) may be possible.

Machine learning modeling and signal processing techniques include but are not limited to supervised and unsupervised algorithms for regression and classification. Specific classes of algorithms include, for example, Artificial Neural Networks (Perceptron, Back-Propagation, Convolutional Neural Networks (e.g., fast-region convolutional neural networks), Recurrent Neural networks, Long Short-Term Memory Networks, Deep Belief Networks), Bayesian (Naive Bayes, Multinomial Bayes and Bayesian Networks), clustering (k-means, Expectation Maximization and Hierarchical Clustering), ensemble methods (Classification and Regression Tree variants and Boosting), single or multiple linear regression, wavelet analysis, fast Fourier transforms, instance-based (k-Nearest Neighbor, Self-Organizing Maps and Support Vector Machines), regularization (Elastic Net, Ridge Regression and Least Absolute Shrinkage Selection Operator), and dimensionality reduction (Principal Component Analysis variants, Multidimensional Scaling, Discriminant Analysis variants and Factor Analysis). In some embodiments, any number of the foregoing algorithms are not included. In several embodiments, the TensorFlow open-source software library may be used to perform machine learning algorithms. Neural networks may be trained, stored, and implemented on the QPCD system 120 e.g., the image processing module 124 and/or quantifier/score calculator module 126).

FIG. 8 illustrates a schematic flow diagram of an embodiment of training a neural network for use and then using the neural network in performing one or more of the steps of the processes described herein (e.g., identifying and quantifying indicators and determining quantitative scores or other output). The neural network may be trained using spinal images of hundreds or thousands of subjects. The images may be from databases of stored images accessible by the QPCD system 120 over the network 104. The spinal images may comprise images of all or portions of a spinal anatomy (e.g., one or more regions of a vertebral column or spine, such as a lumbosacral region).

The spinal images may comprise images from past patients who had visually or manually identified indicators of back pain (e.g., a particular source or type of back pain, such as chronic low back pain) and that were treated by a particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure such as the INTRACEPT® Procedure offered commercially by Relievant Medsystems, Inc.), either successfully or unsuccessfully. The spinal images for training may also include images from patients who have been treated by spinal procedures for treatment of back pain other than basivertebral nerve ablation procedures (such as fusion, vertebral tumor ablation, vertebral fracture treatment, intervertebral disc ablation, or discectomy). In some instances, these other spinal procedures may also involve irritation of vertebral endplates that can result in biomarkers or other indicators of back pain (e.g., chronic low back pain), such as the biomarkers or indicators described herein. The images may also comprise images from healthy (e.g., pristine) subjects that do not have identified indicators of back pain (e.g., a particular source or type of back pain). In some embodiments, the images are MRI images (e.g., T1-weighted MRI images, T2-weighted MRI images, fat-suppression MRI images, UTE MRI images, IDEAL MRI images). In some embodiments, the images may also include images obtained by other modalities (e.g., CT, SPECT, PET, X-ray, and/or others). The images for each subject may comprise sequential images over a period of time or images at a single point in time. The training may involve comparison of images of patients taken before and after a spinal procedure (e.g., before and after a basivertebral nerve ablation procedure) to provide training on variables that may change pre- and post-treatment.

The training may involve applying pre-processing techniques to the images to facilitate feature extraction or detection. MRI images, for example, can be grainy, noisy, blurry, in at least some portions (e.g., due to artifacts caused by patient movement or metallic elements, differences in setup parameters within MRI sequences, differences in Tesla magnetic field strength, poor spatial resolution or image contrast, poor signal to noise ratio or contrast to noise ratio, improper signal weighting, truncation artifacts, aliasing, chemical shift artifacts, cross-talk, etc.). The pre-processing techniques may include, for example, rotating, aligning, re-sizing, cropping, denoising (e.g., removing artifacts, noise, grain), segmenting, smoothing, contrast or color enhancing, making intensity levels more uniform or consistent, applying filters, cleaning up, image reconstruction, and/or other image processing techniques. Rotation and alignment may be performed on the MRI images because the images may depend on patient orientation within the MRI machine, as well as other factors. Re-sizing may be needed to zoom in on the areas of the images were indicators are most likely to occur and to crop out the areas of the images that are irrelevant to the indicators. Pre-processing may also involve dividing the images into a grid of nodes or areas that can be numbered and that are uniform between each training image so as to facilitate feature extraction and comparison of images. The pre-processing may also include spatial orientation identification, vertebral level identification, general anatomical feature identification, and/or the like. In accordance with several embodiments, the pre-processing techniques advantageously result in more uniform images so as to improve training speed and accuracy of the neural network.

In some embodiments, the pre-processing may be targeted to only portions of the images that are deemed to be of interest (e.g., portions of the vertebral anatomy likely to exhibit indicators of back pain that may be effectively treated by the particular spinal neuromodulation procedure). In accordance with several embodiments, if pre-processing is not performed on the images (e.g., MRI images), the output may be less accurate due to poor image quality that results in less-than-ideal feature extraction or detection.

Training may further include performing automated feature extraction, or detection, techniques. Training may involve performing object detection tasks to recognize an object and object localization tasks to evaluate coordinates of a bounding box in which the object is situated in the image. For example, the feature extraction may include pixel/voxel color value comparison techniques, pixel/voxel signal intensity comparison techniques, analysis of variance techniques, cluster analysis techniques, image comparison techniques by comparing with an image of a normal healthy patient without back pain indicators, and/or other feature detection techniques. In some embodiments, feature extraction or detection may be partially or completely performed manually by one or more users (e.g., drawing boundaries of a bounding box surrounding particular features in the images or labelling features using a pen mouse or other user interface or user input tool). In some embodiments, training images may be provided with annotation data or tags (e.g., in a comma-separated values (CSV) file) with information about vertebral level identification, presence of indicators of back pain (e.g., vertebral endplate defects or degeneration, bone marrow intensity changes, or other indicators describe herein), location of indicators, orientation of indicators, extent of indicators, patient-reported outcomes before or after treatment (e.g., VAS scores, ODI scores, quality of life measures such as QoL or EQ scores, patient reported outcome measures, etc. In some embodiments, the annotation data may include tags that identify what the output for that particular image should be (e.g., the quantitative or objective score, value or other output indicative of whether the particular spinal neuromodulation procedure is likely to be successful). The annotation data may also include tags that identify a binary classification output of YES or NO as to whether the particular spinal neuromodulation procedure was effective, or successful, for the patient associated with the image(s). The annotation data may be provided by more than one clinician so as to generate more reliable scores.

An unsupervised neural network may be used to identify patterns to classify or extract features. For example, the neural network may involve use of classification algorithms that include clustering (k-means, Expectation Maximization and Hierarchical Clustering), ensemble methods (Classification and Regression Tree variants and Boosting), instance-based (k-Nearest Neighbor, Self-Organizing Maps and Support Vector Machines), regularization (Elastic Net, Ridge Regression and Least Absolute Shrinkage Selection Operator), and dimensionality reduction (Principal Component Analysis variants, Multidimensional Scaling, Discriminant Analysis variants and Factor Analysis) to classify or extract features that may correlate to indicators of back pain (e.g., a particular type or source of back pain). The neural network may also use TensorFlow software code modules. Although described primarily in connection with back pain (e.g., chronic low back pain), the training of neural networks and quantitative prediction techniques described herein may also be applied to other types of back pain (e.g., middle or upper back pain), neck pain, shoulder pain, peripheral nerve pain (e.g., pain in the wrists, arms, elbows, legs, knees, ankles). The images processed would include images of the respective anatomical portions and the indicators would be identified that correspond to the respective bones involved.

Spinal Neuromodulation Procedure

Any of the processes described herein may also comprise treating a patient by performing the particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure). The treatment devices (e.g., treatment probes) used to perform the particular spinal neuromodulation procedure (e.g., basivertebral nerve ablation procedure) may be any device capable of modulating tissue (e.g., nerves, tumors, bone tissue). Any energy delivery device capable of delivering energy can be used (e.g., radiofrequency energy delivery devices, microwave energy delivery devices, laser devices, infrared energy devices, resistive heating devices, other electromagnetic energy delivery devices, ultrasound energy delivery devices, and the like). The treatment device may be an RF energy delivery device. The RF energy delivery device may include a bipolar pair of electrodes at a distal end portion of the device. The bipolar pair of electrodes may include an active tip electrode and a return ring electrode spaced apart from the active tip electrode. The RF energy delivery device may include one or more temperature sensors (e.g., thermocouples, thermistors) positioned on an external surface of, or embedded within, a shaft of the energy delivery device. The RF energy delivery device may not employ internally circulating cooling, in accordance with several implementations.

In some implementations, water jet cutting devices may be used to modulate (e.g., denervate) nerves. In some implementations, a chemical neuromodulation tool injected into a vertebral body or at an endplate may be used to ablate or otherwise modulate nerves or other tissue. For example, the chemical neuromodulation tool may be configured to selectively bind to a nerve or endplate. In some implementations, a local anesthetic (e.g., liposomal local anesthetic) may be used inside or outside a vertebral body or other bone to denervate or block nerves. In some implementations, brachytherapy may be used to place radioactive material or implants within the vertebral body to deliver radiation therapy sufficient to ablate or otherwise denervate the vertebral body. Phototherapy may be used to ablate or otherwise modulate nerves after a chemical or targeting agent is bound to specific nerves or to a vertebral endplate.

In accordance with several implementations, thermal energy may be applied within a cancellous bone portion (e.g., by one or more radiofrequency (RF) energy delivery instruments coupled to one or more RF generators) of a vertebral body. The thermal energy may be conducted by heat transfer to the surrounding cancellous bone, thereby heating up the cancellous bone portion. In accordance with several implementations, the thermal energy is applied within a specific frequency range and having a sufficient temperature and over a sufficient duration of time to heat the cancellous bone such that the basivertebral nerve extending through the cancellous bone of the vertebral body is modulated. In several implementations, modulation comprises permanent ablation or denervation or cellular poration (e.g., electroporation). In some implementations, modulation comprises temporary denervation or inhibition. In some implementations, modulation comprises stimulation or denervation without necrosis of tissue.

For thermal energy, temperatures of the thermal energy may range from about 60 to about 115 degrees Celsius (e.g., from about 60 to about 80 degrees Celsius, from about 70 to about 90 degrees Celsius, from about 75 to about 90 degrees Celsius, from about to about 75 degrees Celsius, from about 68 to about 78 degrees Celsius, from about 83 to about 87 degrees Celsius, from about 80 to about 100 degrees Celsius, from about 85 to about 95 degrees Celsius, from about 90 to about 110 degrees Celsius, from about 95 to about 115 degrees Celsius, from about 70 to about 115 degree Celsius, or overlapping ranges thereof). The temperature ramp may range from 0.1-5 degrees Celsius/second (e.g., 0.1-1.0 degrees Celsius/second, 0.25 to 2.5 degrees Celsius/second, 0.5-2.0 degrees Celsius/second, 1.0-3.0 degrees Celsius/second, 1.5-4.0 degree Celsius/second, 2.0-5.0 degrees Celsius/second). The time of treatment may range from about 10 seconds to about 1 hour (e.g., from 10 seconds to 1 minute, 1 minute to 5 minutes, from 5 minutes to 10 minutes, from 5 minutes to 20 minutes, from 8 minutes to 15 minutes, from 10 minutes to 20 minutes, from 15 minutes to 30 minutes, from 20 minutes to 40 minutes, from 30 minutes to 1 hour, from 45 minutes to 1 hour, or overlapping ranges thereof). Pulsed energy may be delivered as an alternative to or in sequence with continuous energy. For radiofrequency energy, the energy applied may range from 350 kHz to 650 kHz (e.g., from 400 kHz to 600 kHz, from 350 kHz to 500 kHz, from 450 kHz to 550 kHz, from 500 kHz to 650 kHz, overlapping ranges thereof, or any value within the recited ranges, such as 450 kHz±5 kHz, 475 kHz±5 kHz, 487 kHz±5 kHz). A power of the radiofrequency energy may range from W to 100 W (e.g., from 5 W to 15 W, from 5 W to 20 W, from 5 W to 30 W, from 8 W to 12 W, from 10 W to 25 W, from 15 W to 25 W, from 20 W to 30 W, from 8 W to 24 W, from 5 W to 50 W, from 10 W to 20 W, from 20 W to 50 W, from 25 W to 75 W, from 50 W to 100 W, and overlapping ranges thereof, or any value within the recited ranges).

In accordance with several implementations, a thermal treatment dose (e.g., using a cumulative equivalent minutes (CEM) 43 degrees Celsius thermal dose calculation metric model) is between 200 and 300 CEM (e.g., between 200 and 240 CEM, between 230 CEM and 260 CEM, between 240 CEM and 280 CEM, between 235 CEM and 245 CEM, between 260 CEM and 300 CEM) or greater than a predetermined threshold (e.g., greater than 240 CEM), or a thermal treatment dose equivalent using an Arrhenius model. The CEM number may represent an average thermal cumulative dose value at a target treatment region or location and may represent a number that expresses a desired dose for a specific biological end point. Thermal damage may occur through necrosis or apoptosis.

Cooling may optionally be provided to prevent surrounding tissues from being heated during the nerve modulation procedure. The cooling fluid may be internally circulated through the delivery device from and to a fluid reservoir in a closed circuit manner (e.g., using an inflow lumen and an outflow lumen). The cooling fluid may comprise pure water or a saline solution having a temperature sufficient to cool electrodes (e.g., 2-70 degrees Celsius, 2-10 degrees Celsius, 5-10 degrees Celsius, 5-15 degrees Celsius, 20-50 degrees Celsius, 40-70 degree Celsius, overlapping ranges thereof, or any value within the recited ranges). Cooling may be provided by the same instrument used to deliver thermal energy (e.g., heat) or a separate instrument. In some implementations, cooling is delivered to the region (e.g., the cooling fluid exits the fluid delivery instrument). In accordance with several implementations, cooling is not used.

In some implementations, ablative cooling may be applied to the nerves or bone tissue instead of heat (e.g., for cryoneurolysis or cryoablation applications). The temperature and duration of the cooling may be sufficient to modulate intraosseous nerves (e.g., ablation, or localized freezing, due to excessive cooling). The cold temperatures may destroy the myelin coating or sheath surrounding the nerves. The cold temperatures may also advantageously reduce the sensation of pain. The cooling may be delivered using a hollow needle under fluoroscopy or other imaging modality.

In some implementations, one or more fluids or agents may be delivered to a target treatment site to modulate a nerve. The agents may comprise bone morphogenetic proteins, for example. In some implementations, the fluids or agents may comprise chemicals for modulating nerves (e.g., chemoablative agents, alcohols, phenols, nerve-inhibiting agents, or nerve stimulating agents). The fluids or agents may be delivered using a hollow needle or injection device under fluoroscopy or other imaging modality. Although spinal neuromodulation procedures are specifically discussed herein, other neuromodulation (e.g., peripheral neuromodulation procedures) may be performed.

Terminology

In some implementations, the system comprises various features that are present as single features (as opposed to multiple features). For example, in one embodiment, the system includes a single radiofrequency generator, a single introducer cannula with a single stylet, a single radiofrequency energy delivery device or probe, and a single bipolar pair of electrodes. A single thermocouple (or other means for measuring temperature) may also be included. Multiple features or components are provided in alternate embodiments.

In some implementations, the system comprises one or more of the following: means for quantitatively predicting a scored indicative of likelihood of a patient responding favorably to treatment, means for tissue modulation (e.g., an ablation or other type of modulation catheter or delivery device), means for imaging (e.g., MRI, CT, fluoroscopy), means for accessing (e.g., introducer assembly, curved cannulas, drills, curettes), etc.

Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Although the terms “first” and “second” may be used herein to describe various features/elements (including steps), these features/elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed below could be termed a second feature/element, and similarly, a second feature/element discussed below could be termed a first feature/element without departing from the teachings of the present invention.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising” means various components can be co-jointly employed in the methods and articles (e.g., compositions and apparatuses including device and methods). For example, the term “comprising” will be understood to imply the inclusion of any stated elements or steps but not the exclusion of any other elements or steps.

As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word “about” or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and/or position to indicate that the value and/or position described is within a reasonable expected range of values and/or positions. For example, a numeric value may have a value that is +/−0.1% of the stated value (or range of values), +/−1% of the stated value (or range of values), +/−2% of the stated value (or range of values), +/−5% of the stated value (or range of values), +/−10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value “70” is disclosed, then “about 70” is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that “less than or equal to” the value, “greater than or equal to the value” and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value “X” is disclosed the “less than or equal to X” as well as “greater than or equal to X” (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data, represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments one or more method steps may be skipped altogether. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. The section headings used herein are merely provided to enhance readability and are not intended to limit the scope of the embodiments disclosed in a particular section to the features or elements disclosed in that section. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. The methods disclosed herein include certain actions taken by a practitioner; however, they can also include any third-party instruction of those actions, either expressly or by implication. The term “embodiment” should not be limited to an interpretation as the “invention” and can mean a non-limiting example, implementation or aspect. 

1-76. (canceled)
 77. A computer-implemented method of quantitatively predicting likelihood that a particular subject would respond favorably to basivertebral nerve ablation to treat back pain, the computer-implemented method comprising: receiving one or more magnetic resonance images (MRIs) of at least a portion of a spine of the particular subject; applying pre-processing imaging techniques to the one or more MRIs; extracting features from the one or more MRIs to identify a plurality of indicators of back pain, wherein the plurality of indicators comprises at least one of: (i) bone marrow intensity changes and (ii) vertebral endplate defects or characteristics of vertebral endplate degeneration; and determining an objective score indicative of a likelihood that the particular subject would respond favorably to basivertebral nerve ablation based on said extracting.
 78. The computer-implemented method of claim 77, further comprising applying one or more rules on the extracted features to generate a confidence level.
 79. The computer-implemented method of claim 78 wherein the one or more rules are based on one or more additional indicators.
 80. The computer-implemented method of claim 79, wherein the one or more additional indicators comprise one or more of the following: changes in multifidus muscle characteristics; bone turnover in single-photon emission computed tomography images; and a pain score obtained for the particular subject.
 81. The computer-implemented method of claim 77, further comprising quantifying the identified plurality of indicators of back pain, wherein the quantifying the identified plurality of indicators comprises one or more of: determining a quantity of the bone marrow intensity changes or vertebral endplate defects; determining a level of extent of the bone marrow intensity changes or vertebral endplate defects; and quantifying identified fat fraction changes.
 82. The computer-implemented method of claim 77, wherein the back pain is chronic low back pain.
 83. The computer-implemented method of claim 77, wherein at least some of the MRIs comprise T1-weighted MRIs, T2 weighted MRIs or fat suppression MRIs.
 84. The computer-implemented method of claim 77, wherein at least some of the MRIs are generated using ultrashort time-to-echo MRI techniques or least-squares estimation MRI techniques.
 85. The computer-implemented method of claim 77, wherein the extracting features from the one or more MRIs to identify the plurality of indicators of back pain comprises applying a trained neural network to the one or more MRIs to automatically identify the plurality of indicators of back pain.
 86. The computer-implemented method of claim 77, wherein the extracting features from the one or more MRIs to identify the plurality of indicators of back pain comprises one or more of: identifying irregularities or deviations to a normal continuous lining of the vertebral endplate; identifying deviations from a normal contour profile of a vertebral endplate; identifying fat fraction changes; and identifying one or more phenotype subtypes of vertebral endplate defects.
 87. The computer-implemented method of claim 77, further comprising displaying an output of the objective score on a display.
 88. The computer-implemented method of claim 77, wherein the plurality of indicators comprises both (i) bone marrow intensity changes and (ii) vertebral endplate defects or characteristics of vertebral endplate degeneration.
 89. The computer-implemented method of claim 77, wherein the objective score is used to generate a recommendation for treatment.
 90. A computer-implemented method of quantitatively predicting likelihood that a particular subject would respond favorably to basivertebral nerve ablation to treat back pain, the method comprising: receiving one or more images of at least a portion of a spine of the particular subject; applying pre-processing imaging techniques to the one or more images; extracting features from the one or more images to identify a plurality of indicators of back pain, wherein the plurality of indicators comprises at least one of: (i) bone marrow intensity changes and (ii) vertebral endplate defects or characteristics of vertebral endplate degeneration; and determining an objective score indicative of a likelihood that the particular subject would respond favorably to basivertebral nerve ablation based on said extracting.
 91. The computer-implemented method of claim 90, further comprising quantifying the identified plurality of indicators of back pain, wherein the quantifying the identified plurality of indicators comprises one or more of: determining a quantity of the bone marrow intensity changes or vertebral endplate defects; determining a level of extent of the bone marrow intensity changes or vertebral endplate defects; and quantifying identified fat fraction changes.
 92. The computer-implemented method of claim 90, further comprising applying one or more rules on the extracted features to generate a confidence level.
 93. The computer-implemented method of claim 92, wherein the one or more rules are based on one or more additional indicators.
 94. The computer-implemented method of claim 93, wherein the one or more additional indicators comprise one or more of the following: changes in multifidus muscle characteristics; bone turnover in single-photon emission computed tomography images; and a pain score obtained for the particular subject.
 95. The computer-implemented method of claim 90, further comprising displaying an output of the objective score on a display.
 96. The computer-implemented method of claim 90, wherein the extracting features from the one or more images to identify the plurality of indicators of hack pain comprises applying a trained neural network to the one or more images to automatically identify the plurality of indicators of back pain.
 97. The computer-implemented method of claim 90, wherein the one or more images comprise one or more of: magnetic resonance images, computed tomography images, X-ray images, and single-photon emission computed tomography images. 